Recent Advances in Esophageal Function Testing for Functional Esophageal Disorders

Functional esophageal disorders are heterogeneous conditions characterized by esophageal symptoms without definite structural obstruction or major mucosal disease. Recent advances in high-resolution manometry, the Chicago Classification version 4.0, provocative maneuvers, timed barium esophagography, and functional lumen imaging probe have substantially changed the diagnostic approach to these disorders. Although high-resolution manometry remains the cornerstone of esophageal motility assessments, normal or borderline manometric findings do not always indicate a normal esophageal physiology. In particular, the integrated relaxation pressure has important limitations because it reflects pressure-based relaxation rather than actual esophagogastric junction opening. A functional lumen imaging probe provides complementary information by assessing esophagogastric junction distensibility and distension-induced contractile responses. This approach may reveal subtle obstructive physiology, impaired distensibility, or abnormal wall biomechanics that are not evident on conventional manometry. Emerging concepts, such as manometry-functional lumen imaging probe discordance, esophageal wall thickening-associated dysphagia, and distension-mediated obstruction, suggest that some patients previously diagnosed with functional dysphagia may have identifiable and potentially treatable physiologic abnormalities. Therefore, the evaluation of functional esophageal disorders is moving from exclusion-based diagnoses toward multimodal, symptom-oriented physiologic phenotyping.